Spotify drilldown filter

SpotifyDrilldown.swift

import SwiftUI

struct SpotifyToggle: View {
  let value: String
  @Binding var selection: String?
  let didTap: () -> Void
  var body: some View {
    Toggle(value, isOn: .init(get: { selection == value }, set: { _ in
      withAnimation {
        if selection == nil {
          selection = value
        }
        didTap()
      }
    }))
    .toggleStyle(.button)
    .tint(.white)
    .buttonStyle(.bordered)
    .buttonBorderShape(.capsule)
    .transition(.blurReplace)
  }
}

struct SpotifyDrilldown: View {
  @State private var selection: String?
  @State private var subSelection: String?
  var body: some View {
    HStack {
      ForEach([ "Playlists", "Artists", "Albums" ], id: \.self) { filter in
        if selection == nil || filter == selection {
          if selection != nil {
            Button {
              withAnimation {
                selection = nil
                subSelection = nil
              }
            } label: { Image(systemName: "xmark") }
            .tint(.white)
            .buttonStyle(.bordered)
            .buttonBorderShape(.circle)
            .transition(.blurReplace)
          }
          SpotifyToggle(value: filter, selection: $selection) {
            subSelection = nil
          }
          let filterSubFilters = [ "Playlists": [ "By Spotify", "By you" ] ]
          if selection != nil, let subFilters = filterSubFilters[filter] {
            ForEach(subFilters.filter { subSelection == nil || subSelection == $0 }, id: \.self) { subFilter in
              SpotifyToggle(value: subFilter, selection: $subSelection) { }
            }
          }
        }
      }
    }
    .frame(maxWidth: .infinity, alignment: .leading)
  }
}

#Preview {
  SpotifyDrilldown()
    .padding()
}